Rotary engine

ABSTRACT

In a rotary engine there is provided a stator having a cavity in which a rotor is mounted for rotation about a fixed axis of rotation. Between the stator and rotor there is formed an annular space including a relatively narrow, concentric, intermediate space segment between a larger upstream space segment and a larger downstream space segment effecting a relatively high compression of a fuel-air mixture induced into the upstream space segment by rotation of the rotor. The rotor has radially movable vanes which ride on stationary cam surfaces at each end thereof and are urged outwardly against the inner wall of the stator with sealing rings carried on the vanes and between the stator and rotor which divide the annular space into separate working chambers. A fuel-air mixture is successively induced through an inlet port in the stator into the upstream space segment where it is then compressed and ignited in the intermediate space segment to propel the rotor. The resulting products of combustion are exhausted via the downstream space segment and through an outlet port in the stator for each revolution of each vane.

United States Patent 1 Bakes [111 3,863,611 Feb. 4, 1975 ROTARY ENGINE[76] Inventor: Stefan Bak0s, 418l S. Verbena,

Denver, Colo. 80237 221 Filed: May 7,1973

211 App]. No.: 358,056

Primary Examiner--Carlt0n R. Croyle Assistant Examiner-O. T. SessionsAttorney, Agent, or Firm-Ancel W. Lewis, Jr.

[57] ABSTRACT In a rotary engine there is provided a stator having acavity in which a rotor is mounted for rotation about a fixed axis ofrotation. Between the stator and rotor there is formed an annular spaceincluding a relatively narrow, concentric, intermediate space segmentbetween a larger upstream space segment and a larger downstream spacesegment effecting a relatively high compression of a fuel-air mixtureinduced into the upstream space segment by rotation of the rotor. Therotor has radially movable vanes which ride on stationary cam surfacesat each end thereof and are urged outwardly against the inner wall ofthe stator with sealing rings carried on the vanes and between thestator and rotor which divide the annular space into separate workingchambers. A fuel-air mixture is successively induced through an inletport in the stator into the upstream space segment where it is thencompressed and ignited in the intermediate space segment to propel therotor. The resulting products of combustion are exhausted via thedownstream space segment and through an outlet port in the stator foreach revolution of each vane.

7 Claims, 8 Drawing Figures anF- SHEET PATENTEUFEB 41975 I'l l l l l l ll nl l lMJHJI I I I H HHI L I ROTARY ENGINE BACKGROUND OF THE INVENTIONThis invention relates to rotary-type internal combus tion engines.

Rotary-type internal combustion engines in general offer a distinctadvantage over piston-type engines in that there are no reciprocatingpistons which have to be alternately accelerated and retarded. The mostcommonly know rotary-type engine is the Wankel engine which in generalhas a triangular shaped rotor with three convexly curved sides mountedfor rotation in a stator having an internal cavity of a generally ovalshape. The rotor is mounted for rotation about an eccentrically movingaxis of rotation as distinguished from a fixed axis of rotation whichconstruction has a tendency to cause difficulty with seals between theworking chambers formed between the rotor and stator and to cause anundue amount of wear and deleterious vibration on the rotor and stator.

Accordingly, it is a general object of this invention to provide a novelrotary-type engine having a plurality of working chambers formed betweenthe stator and rotor and principally characterized by having a highcompression of the fuel-air mixture, being smooth in operation andavoiding undue part wear.

Another object of this invention is to provide a rotary-type enginewhich is considerably easier to seal between the multiple workingchambers and between the stator and rotor and affords a highercompression of the fuel-air mixture than previously known rotary-typeengines.

Still a further object of this invention is to provide a rotary-typeengine characterized by having a rotor that rotates about a fixed axisof rotation and radially reciprocatingvanes having inner ends which moveon stationary cam surfaces throughout each revolution together withsealing rings at the outer ends of the vanes and between the stator androtor which confine the fuel-air mixture during rotation of the rotor insuch a way as to carry out induction of a fuel-air mixture, a relativelyhigh compression of the fuel-air mixture, ignition and exhaust of theproducts of combustion in an annular space formed between the stator androtor as the rotor is rotated.

In accordance with the present invention in a preferred embodiment shownthere is provided a stator with a cavity having a generally eccentrictransverse contour in which a rotor body with a circular cross sectionis rotated about a fixed axis forming an annular space between thestator and rotor. The rotor has circumferentially spaced, radiallyreciprocating vanes which are urged by stationary cam surfaces at eachend of the rotor against the inner peripheral wall of the stator to formworking chambers between adjacent vanes as the rotor is rotated. Afuel-air mixture is induced through an inlet port in the stator into anupstream space segment and is then compressed and ignited in arelatively narrow, concentric, space segment followed by having a vanemove the resulting products of combustionthrough a downstream spacesegment'and out an exhaust port in the stator. Sealing rings areprovided between the vanes and the stator and between the statorandrotor to confine the fuel-air mixture to the working chambers. Alubricating system, provides lubrication for the reciprocating vanes andsealing rings.

Other objects, advantages and capabilities of the present invention willbecome more apparent as the description proceeds taken in conjunctionwith the accompanying drawings in which:

FIG. I is a perspective view of a rotary engine embodying features ofthe present invention with some parts exploded and separated forclarity;

FIG. 2 is a vertical sectional view through the center of the enginealong longitudinal axis thereof with one of the vanes disposed in theupright or straight-up position;

FIG. 3 is a sectional view taken along lines 3-3 of FIG. 2;

FIG. 4 is a sectional view taken along lines 4-4 of FIG. 2;

FIG. 5 is a perspective view of a corner portion of the rotor;

FIG. 6 is a perspective view of one of the vanes;

FIG. 7 is an end elevation view of one of the vanes;

FIG.- 8 is a sectional view taken along lines 8-8 through the vane ofFIG. 7.

Referring now to the drawings, there is shown a rotary engine which, ingeneral, comprises a stator S having an internal cavity K in which thereis mounted for rotation a rotor R. In general, the internal peripheralsurfaces of the stator defining the cavity together with the externalperipheral surfaces of the rotor form an annular space described morefully hereinafter. The rotor R has radially extending vanes designatedVA, VB and VC which are mounted for reciprocating movement; the rotor Rbeing arranged for rotation about a fixed axis of rotation at the centerof the stator and rotor designated X in FIG. 3..

The stator S has a main housing 21 open at the ends with the cavity Kformed therein as a throughbore and end caps 22 and 23 close the ends ofthe housing and define the end boundaries of the internal cavity K. Theend caps are shown as being held in place on the housing 21 by bolt-typefasteners F.

The contour or shape of the inner peripheral surface of the housingdefining the cavity K is broken into several distinct concave and convexarcs or segments of a circle some of which are eccentric relative to thecenter of the cavity and axis of rotation for the rotor designated X.With particular reference to FIG.3, the arcs or radii of circles makingup the contour of the inner peripheral surface of the stator are betweenpoints designated by numerals l and 2, 2 and 3, 3 and 4, 4 and 5, 5 and6, 6 and 7, 7 and 8, and i8 and 1. The arcs between points 3 and 4, 4and 5, and 8 and l are convex' arcs which have a center point externallyof the housing while the other arcs have a center point inside thehousing and only the arc between points 4 and 5 is measured from thecenter of the housing and is concentric with axis X. Aconcave generallyV-shaped recess 24 is provided in the housing at a position. about 225from the reference at 0 as measured in a clockwise direction as shown inFIG. 3.

The main housing 21 has two fuel-air mixture inlet passages 25 in thetop thereof with associated inlet ports 250 located at the arc betweenpoints 8 and I to the right side of a vertical dividing line through thehousing as viewed in FIG. 3 through which a mixture. of fuel and air isinduced into the annular space as described hereinafter and an exhaustoutlet passages 26 in the top thereof with an outlet ports 26a in theare between points 8 and l on the left side of the vertical-dividingline through the housing. The inlet and outlet passages leave bridges onthe sides and at the center of the housing. The main housing 21 furtherhas communicating internal spaces 27 forming a waterjacket for coolingand bolt holes 28 for fastening the end caps to the housing withsuitable fasteners with bolts F. The housing 21 also supports anignition element 29 in the form of a spark plug mounted at the 225position.

The end caps 22 and 23 are similar in construction and are shown asbeing made up of inner and outer plates designated 31 and 32,respectively, which are separable from one another for convenience ofmanufacture. Each inner plate 31 has a circular recess 33 in the innerface sized to receive an end portion of the rotor R leaving an outeroverhanging portion 34 and a central protruding hub portion 35. Eachinner hub portion 35 is externally contoured to provide a cam surface35a similar in shape to that of the inner peripheral surface of thestator forming the cavity over which the inner ends of the vanes move sothat the vanes at all times are urged outwardly against the innerperipheral surface of the housing during the rotation of the rotor. Eachouter plate 32 has a circular recess 37 in the inner face thereof andeach inner plate 31 has a circular recess 38 matching recess 37 to forman oil reservoir L in the end caps for lubrication purposes as describedhereinafter. A flywheel 39 is mounted for rotation in one of thereservoirs in-end cap 22 to assist in circulating the lubricating oil toand from reservoir L.

The rotor R has a main rotor body 41 that is circular in transversecross section and generally cylindrical in shape with three radiallyextending slots 43 located at 120 intervals around the rotor body whichslidably receive and support the three vanes VA, VB and VC for areciprocating movement therein. The radial slots 43 do not extend thefull length of the rotor body leaving circumferentially continuous outeroverhanging end portions 44 at each end of the rotor body. The rotorbody 41 further has a circular radial groove 45 .at each end formed inthe outer peripheral surface thereof adjacent the ends of the radialslots each receiving a sealing ring 46. Sealing ring 46 is of aconstruction similar to a piston ring in an engine with an expansionslot formed therein and engages the inner axial surface of plate 31 toform a seal between the stator and rotor. The rotor body 41 further hasa circular radial groove 47 in each end thereof for receiving a sealingring assembly inclusive of an outer ring 48, intermediate spring 49 andinner ring 50, the ring 48 bearing against a section of the inner ring55. Inner ring 55 forms a continuous loop along the ends in groove47'which extends through a groove 51. The portion of ring 55 in groove47 bears against the inside of the vane to provide a seal between therotor body 41 and the outer side edges of each of the vanes and theportion of ring 55 in groove 51 bears against the face of the vane toconfine the fuel-air mixture to the working chambers.

The rotor body 41 is undercut at each end leaving an overhanging outerend portion 44 and an inner hub portion 52 of cylindrical shape which isprovided with internal gear teeth 53. The rotor body 41 is supported forrotation by the stator with a bearing 54 at each end. The inner hubportion 52 extends inside and is affixed to the inner race of thebearing 54 and the outer race is mounted in and affixed to the hubportion 35 of the end cap.

An output shaft 56 is mounted for rotation within the inner hub portions52 of the rotor body in bearings 57 at each end thereof. The bearingsare affixed to the end caps and are specifically shown as recessed inthe hub portion of the outer plate 32. The output shaft 56 has externalgear teeth 58 which mesh with the internal gear teeth 53 in the hubportion of the rotor body to provide a speed reduction in the outputshaft 56 from that of the rotor body 41. A two-to-one speed reduction ispreferred but it is understood the speed may be increased or decreasedbetween the rotor body and output shaft.

The vanes VA, VB and VC are of identical construction and each comprisea main vane body 61 of generally oblong shape with smooth flat sides andends which slide freely into an associated generally U-shaped radialslot 43 in the rotor body and reciprocate therein as the rotor body isrotated. The lower end of the vane body engaging the cam surface isrounded at 61a and bearings 62 in the form of sleeves are provided ateach end ,rollable on shaft sections 63 to reduce the friction. The

outer edge of the vane body 61 has a circular groove 65 extendingthrough an arc of greater than 180 in which there is mounted a rotatablehead 66 which rotates about its center in and relative to the groove asthe angular position of the vane changes relative to the stator housing21. The head 66 has a generally circular transverse cross section with apair of radially projecting ear portions 66a and 66b. A slot 67 isprovided in the head, between the ear portions which receives a spring68 and a ring 69 to effect a moving seal between the outer edge of thevane and the inside of the stator housing as the rotor rotates and thecam surface 35a urges the ring into engagement throughout a fullrevolution of the rotor.

In the engine assembly as best seen in FIG. 2, the peripheral sealingrings 46 engage an inner axial wall portion 33a of the inner plate 31and the end sealing ring 48 engages the inner axial wall 33b of theinner plate 31. Rings 46 also engage the outer side edges of the vanesto seal across the ends thereof as best seen in FIG. 5. The vanes VA, VBand VC travel in a path established by the stationary cam and cavitysurfaces of the stator with the heads 66 rotating so that ring 69 is atall times flush against the cavity surface.

For the lubrication of the vanes in their associated slots the oil fromthe reservoir L at the ends of the housing is agitated by the flywheel39 and moved into the crescent-shaped space between the shaft 56 andhollow hub portion 52 as best seen in FIG. 2. The vane body 61 has ahole 61a extending therethrough opening into the upper groove 65 at itsupper end and into an opening 35' in the hub and an opening 52' in hub52 leading into the crescent-shaped space between rotor 56 and hub 52.As the vanes rotate about the axis they reciprocate in the slots andthereby pump the oil from the crescent-shaped space and reservoir upinto the groove 65 to lubricate the vanes and the associated sealingring 69.

As best seen in FIG. 3 the annular space formed between the stator androtor is divided into several distinct space segments. For referencepurposes beginning at the 0 position and proceeding in a clockwisedirection as viewed inFIG. 3 the first space segment herein referred toas the upstream space segment and designated S1 spans an arc of aboutmeasured in a clockwise direction from a vertical 0 reference. Thisupstream space segment S1 has a generally crescentlike shape. Theupstream space segment S1 is in communication with the inlet port 25a.Proceeding further in the clockwise direction, the next annular spacesegment herein referred to as the intermediate space segment" isdesignated S2. Segment S2 covers about 120 and is a relatively narrowgap formed by essentially two opposed surfaces of the stator and rotorwhich are concentric relative to axis X. Within this intermediate spacesegment S2 at the downstream end portion thereof at about 225 angle fromthe reference the recess 24 in the stator and opposed concentric rotorsurface forms an enlarged space segment S3 into which a major portion ofthe fuel-air mixture is compressed for ignition. Recess 29 is providedwith brides like passages 25 and 26 to facilitate the sliding movementof the vanes thereover. The ignition element 29 is mounted in thehousing 21 and the spark gap portion thereof is located in the spacesegment S3 to ignite the compressed fuel-air mixture. The gap formingintermediate space segment S2 is shown as being fairly wide in thedrawings for clairity but it is understood that it is quite small toprovide a high compression of the fuel-air mixture and confine themixture to the area of the spark gap of the plug 29. The next annularspace segment between the stator and rotor designated S4 hereinafterreferred to as the downstream space segment extends from the 240 to 360or back to the 0 reference.

As used herein, upstream is with reference to being toward the source ofthe fuel-air mixture and downstream" is with reference to being awayfrom the source of the fuel-air mixture and further in the area at whichthe combustion is being discharged.

It is noted that the convex surface portions between points 1 and 8,points 3 and 4 and points 5 and 6 of the stator are closest to theperiphery of the rotor so that three distinct working chambers arereadily apparent when one of the vanes is upright and the other vaneshave the ring portions engaging a part of the other concave surfaceportions as shown in FIG. 3.

OPERATION.

The complete sequence of operation will now be described with referenceto FIG. 3 taking the vane VA and following its movement in a clockwisedirection from a center upright reference 12 0clock or 0 position.

In the previous cycle just before vane VA reaches the 0 position, gaseshave been induced between vanes VA and VC via intake port 25a. Vane VAthen moves from the 0 position past intake port 25a to position A-l (22)which is the beginning ofthe induction cycle for the fuel-air mixture inthe working chamber between vanes VA and VB. As vane VA moves throughthe upstream space segment S1 to position A-2 (40) more of the fuel-airmixture is drawn or induced into the upstream space segment betweenvanes VA and VB.

At about position A-3 (60) for vane VA the gases which had been inducedbetween vanes VA and VC are beginning to be compressed in the downstreamposition of the crescent-shaped segment 81 between vanes VA and VCcontinues until vane VA is at position A-5 (120). At this point, thefuel-air mixture is fully compressed in the intermediate space segmentS2 and particularly in the compression space S3 between vanes VA, vaneVC and the rotor and stator walls.

With vane VA at the A-5 position the ignition at the spark gap ofelement 29 occurs igniting the compressed fuel-air mixture bet-weenvanes VA and VC which then moves vane VA to the A-9 (240) position whereit is ready for another ignition. This next ignition which is the powerstroke for vane VA which then pushes or propels the rotor further in aclockwise direction by applying forces to the surface of the rotor andin a direction normal to that portion of the vane VA extending beyondthe rotor.

Beginning at position A-9 for vane VA, upstream thereof in thedownstream space segment S4 the exhaust gases from the previous ignitionare started to be swept or forced out the exhaust port 26a and as vaneVA is moved from position A-9 (240) to position A-l2 (315) they areexhausted. The vane VA continues to rotate through downstream spacesegment S4 until it has completed a full revolution and then startsthrough the next cycle in which the same procedure per cycle orrevolution is accomplished for each of the three vanes VA, VB and VC foreach revolution so there are three inductions, compressions, ignitionsand exhausts for each revolution of the rotor.

During the rotation of the rotor body 41 the inner ends of the vanesfollow a course established by cam surface 35a and the outer ends of thevanes follow a course established by the contour of the housing causingthe vanes to reciprocate in the slots. This in turn draws or pumps oilfrom the space between the shaft.

From the foregoing description of the-preferred embodiment, it isapparent that by having the rotor rotate about a fixed axis that therewill be less vibrations and easier to seal between the working chambers.Moreover, the use of principally concentric surfaces in the area ofignition facilitates a high compression of the fuel-air mixture andresults in a high efficiency.

Although the present invention has been described with a certain degreeof particularity, it is understood that the present disclosure has beenmade by way of example and that changes in details of structure may bemade without departing from the spirit thereof.

What is claimed is:

, 1. In a rotary engine the combination comprising:

a stator having a main housing with a'cavity formed as a throughbore andan inlet port for passing a fuel-air mixture into the cavity and anoutlet port for passing products of combustion from the cavity, saidmain housing having a water jacket, and end caps attached to the ends ofthe main housing forming the ends of the cavity, each of said end capshaving a recessed portion in the inner side thereof;

a rotor having a rotor body having three radial slots arranged atintervals with a circular transverse cross. section 'mounted forrotation about a fixed axis in bearings supported in the end caps. saidrotor being undercut in each end forming an inner recess and anoverhanging end portion that projects into the recessed portion in anassociated end cap;

the stator and rotor defining therebetween and annular space including arelatively narrow, intermediate space segment formed by surfacesarranged concentric with the fixed axis and extending through an arebetween about and about 225 from a reference of 0 between the inlet portand 'outlet port, a larger generally crescent-shaped upstream spacesegment in communication with the inlet port formed by concavestator'surfaces arranged eccentric with the fixed axis and extendingthrough an arc between about and 135 from a reference of 0, a largergenerally crescent-shaped downstream space segment in communcation withthe outlet port formed by concave stator surfaces arranged eccentricwith the fixed axis'and extending through an arc between about 225 andabout 360 from the reference of 0, each of said intermediate, upstreamand downstream space segments being joined by a convex stator surfaceformed by a radius having its center externally of the stator; threeradial vanes, each vane having an oblong vane body slidably movable inone of the radial slots, each said vane body having a rounded inner endwith bearing means adapted to move over a cam surface and a circulargroove in the outer end carrying a generally circular head rotatable inthe groove and a sealing ring movable in the head;

a cam on the end caps at each end of the rotor having cam surfacesprojecting into the inner recess of the rotor and having a contoursimilar to that of the stator cavity on which the inner ends of thevanes ride as the rotor is rotated to urge the ring carried by the headagainst the inner peripheral surface of the stator defining the cavitywith the head rotating relative to the vane body;

sealing means between the rotor and the vane body in the slots;

first sealing rings in grooves in the periphery of the overhanging endportion of the rotor body in engagement with recessed portions of theend caps;

second sealing rings in grooves at the ends of the overhanging endportions of the rotor body in enagement with the recessed portions ofthe end caps;

said stator, rotor vanes and sealing means, first sealing rings andsecond sealing rings dividing the annular space into separate workingchambers between each two adjacent vanes to confine the fuelair mixturethereto whereby a fuel-air mixture is successively induced through theinlet port into the upstream space segment between two adjacent vanesand then compressed in the intermediate space segment between twoadjacent vanes upon rotation of the rotor;

an ignition element positioned in the intermediate space segment forigniting the compressed fuel-air mixture just upstream of a vane topropel the rotor and produce products of combustion by the ignitionwhereby movement of the vane moves the resulting products of combustionthrough said downstream space segment and out the outlet port for eachrevolution of each vane.

2. In a rotory engine as set forth in claim 1 wherein each said head hasa pair of spaced radially projecting portions on opposite sides of thesealing ring that engage the inner surface of the stator housing.

3. In a rotoary engine as set forth in claim 1 wherein said ignitionelement is mounted at about 225 in from a reference of 0 and opens intothe intermediate space segment ahead of the downstream space segment.

4. In a rotary engine as set forth in claim 1 wherein said circulargroove in each vane extends through an arc of more than a semi-circle toretain the associated head therein.

5. In a rotary engine as set forth in claim 1 wherein eachcrescent-shaped upstream and downstream space segment is provided by aconcavity in the stator including a first arcuate segment having a firstradius and a second arcuate segment having a second radius, said firstand second radius having different centers internally of the stator andeach having a radius less than the radius of the rotor.

6. In a rotary engine as set forth in claim 1 wherein said vane body hasa passage between the inner end and the outer end to pass a lubricantfrom the rotor body to the groove.

7. In a rotary engine as set forth in claim 1 wherein said rotor has ahub with internal gear teeth, and an output shaft with external gearteeth arranged to reduce the output speed of the output shaft relativeto the movable body.

1. In a rotary engine the combination comprising: a stator having a mainhousing with a cavity formed as a throughbore and an inlet port forpassing a fuel-air mixture into the cavity and an outlet port forpassing products of combustion from the cavity, said main housing havinga water jacket, and end caps attached to the ends of the main housingforming the ends of the cavity, each of said end caps having a recessedportion in the inner side thereof; a rotor having a rotor body havingthree radial slots arranged at 120* intervals with a circular transversecross section mounted for rotation about a fixed axis in bearingssupported in the end caps, said rotor being undercut in each end formingan inner recess and an overhanging end portion that projects into therecessed portion in an associated end cap; the stator and rotor definingtherebetween and annular space including a relatively narrow,intermediate space segment formed by surfaces arranged concentric withthe fixed axis and extending through an arc between about 135* and about225* from a reference of 0* between the inlet port and outlet port, alarger generally crescent-shaped upstream space segment in communicationwith the inlet port formed by concave stator surfaces arranged eccentricwith the fixed axis and extending through an arc between about 0* and135* from a reference of 0*, a larger generally crescent-shapeddownstream space segment in communcation with the outlet port formed byconcave stator surfaces arranged eccentric with the fixed axis andextending through an arc between about 225* and about 360* from thereference of 0*, each of said intermediate, upstream and downstreamspace segments being joined by a convex stator surface formed by aradius having its center externally of the stator; three radial vanes,each vane having an oblong vane body slidably movable in one of theradial slots, each said vane body having a rounded inner end withbearing means adapted to move over a cam surface and a circular groovein the outer end carrying a generally circular head rotatable in thegroove and a sealing ring movable in the head; a cam on the end caps ateach end of the rotor having cam surfaces projecting into the innerrecess of the rotor and having a contour similar to that of the statorcavity on which the inner ends of the vanes ride as the rotor is rotatedto urge the ring carried by the head against the inner peripheralsurface of the stator defining the cavity with the head rotatingrelative to the vane body; sealing means between the rotor and the vanebody in the slots; first sealing rings in grooves in the periphery ofthe overhanging end portion of the rotor body in engagement withrecessed portions of the end caps; second sealing rings in grooves atthe ends of the overhanging end portions of the rotor body in enagementwith the recessed portions of the end caps; said stator, rotor vanes andsealing means, first sealing rings and second sealing rings dividing theannular space into separate working chambers between each two adjacentvanes to confine the fuel-air mixture thereto whereby a fuel-air mixtureis successively induced through the inlet port into the upstream spacesegment between two adjacent vanes and then compressed in theintermediate space segment between two adjacent vanes upon rotation ofthe rotor; an ignition element positioned in the intermediate spacesegment for igniting the compressed fuel-air mixture just upstream of avane to propel the rotor and produce products of combustion by theignition whereby movement of the vane moves the resulting products ofcombustion through said downstream space segment and out the outlet portfor each revolution of each vane.
 2. In a rotory engine as set forth inclaim 1 wherein each said head has a pair of spaced radially projectingportions on opposite sides of the sealing ring that engage the innersurface of the stator housing.
 3. In a rotoary engine as set forth inclaim 1 wherein said ignition element is mounted at about 225* in from areference of 0* and opens into the intermediate space segment ahead ofthe downstream space segment.
 4. In a rotary engine as set forth inclaim 1 wherein said circular groove in each vane extends through an arcof more than a semi-circle to retain the associated head therein.
 5. Ina rotary engine as set forth in claim 1 wherein each crescent-shapedupstream and downstream space segment is provided by a concavity in thestator including a first arcuate segment having a first radius and asecond arcuate segment having a second radius, said first and secondradius having different centers internally of the stator and each havinga radius less than the radius of the rotor.
 6. In a rotary engine as setforth in claim 1 wherein said vane body has a passage between the innerend and the outer end to pass a lubricant from the rotor body to thegroove.
 7. In a rotary engine as set forth in claim 1 wherein said rotorhas a hub with internal gear teeth, and an output shaft with externalgear teeth arranged to reduce the output speed of the output shaftrelative to the movable body.